An effective strategy of constructing a multi-junction structure by integrating a heterojunction and a homojunction to promote the charge separation and transfer efficiency of WO3,Journal of Materials Chemistry A

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An effective strategy of constructing a multi-junction structure by integrating a heterojunction and a homojunction to promote the charge separation and transfer efficiency of WO3
Journal of Materials Chemistry A ( IF 10.7 ) Pub Date : 2020/03/10 , DOI: 10.1039/d0ta00452a
Yanting Li _{1,

2,

3,

4} , Zhifeng Liu _{1,

2,

3,

4,

5} , Junwei Li _{1,

2,

3,

4,

5} , Mengnan Ruan _{1,

2,

3,

4,

5} , Zhengang Guo _{1,

2,

3,

4,

5}

Affiliation

Adequate light absorption and effective charge separation and transfer are deemed to be the contributing factors to achieve high photoelectrochemical (PEC) water splitting on photoanodes. Herein, in this work, a Mo-WO₃/Fe-WO₃ homojunction was fabricated firstly by coating Fe doped WO₃ (Fe-WO₃) on Mo doped WO₃ (Mo-WO₃) via a two-step hydrothermal method, and then Bi₂S₃ nanoparticles (NPs) were further introduced onto the surface of Mo-WO₃/Fe-WO₃ to construct a multi-junction structure. In this Mo-WO₃/Fe-WO₃/Bi₂S₃ photoanode, the Bi₂S₃ NPs as the primary light absorber improve the light utilization efficiency. Moreover, the Fe-WO₃/Bi₂S₃ heterojunction is formed due to their well-matched bands, which could facilitate charge separation and transfer; meanwhile, the internal built-in electric field at the interface of the Mo-WO₃/Fe-WO₃ homojunction would hinder the recombination of electron–hole pairs. Notably, the homojunction can further promote carrier transfer because of its unique property of eliminating the lattice mismatch. As expected, the Mo-WO₃/Fe-WO₃/Bi₂S₃ photoanode yields a significantly enhanced photocurrent of 2.55 mA cm⁻² at 1.23 V vs. RHE, which is 8.23 times that of the WO₃ photoanode. Thus, constructing a multi-junction structure with a ladder staggered alignment by integrating a homojunction and a heterojunction is believed to be an effective strategy to improve the PEC performance of WO₃ photoanodes.

中文翻译：

通过整合异质结和同质结以提高WO3的电荷分离和转移效率来构建多结结构的有效策略

足够的光吸收以及有效的电荷分离和转移被认为是在光电阳极上实现高光电化学（PEC）水分解的重要因素。在此，本工作中，首先通过两步水热法在掺Mo的WO ₃（Mo-WO ₃）上涂覆掺Fe的WO ₃（Fe-WO ₃），从而制得Mo-WO ₃ / Fe-WO ₃同质结。然后，将Bi ₂ S ₃纳米颗粒（NPs）进一步引入到Mo-WO ₃ / Fe-WO ₃的表面上以构建多结结构。在此Mo-WO ₃ / Fe-WO ₃/ Bi ₂ S ₃光电阳极，Bi ₂ S ₃ NPs作为主要的光吸收剂，提高了光的利用效率。此外，由于Fe-WO ₃ / Bi ₂ S _3的能带匹配良好，形成了异质结，可以促进电荷的分离和转移。同时，Mo-WO ₃ / Fe-WO ₃同质结界面处的内部内置电场会阻碍电子-空穴对的复合。值得注意的是，由于同质结具有消除晶格失配的独特性能，因此可以进一步促进载流子转移。不出所料，Mo-WO ₃ / Fe-WO ₃与RHE相比，/ Bi ₂ S ₃光电阳极在1.23 V时产生显着增强的2.55 mA cm ^-2的光电流，这是WO ₃光电阳极的8.23倍。因此，通过整合同质结和异质结来构建具有梯形交错排列的多结结构被认为是提高WO ₃光电阳极的PEC性能的有效策略。

更新日期：2020-04-01

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